Antipick pin tumbler lock



Patented May 31, 1932 UNrED STATES PATENT FFC v LOUIS C. GUTMAN, OF FITCHBURG, MASSACHUSETTS, ASSIGNOR TO-INDEPENDENT LOCKy COIMPANY, F FITCHBURG, MASSACHUSETTS, A CORPORATION OE IVEASSdIlI-Jill'SETTEr ANTIPICK PIN TUMBLER LOCK i y Application mea January 31,` '1930. seriali No'. 4:25pm.

drawings, in which LSU Fig. 1 is a side view of the cylinder of a lock constructed in accordance with this invention, partly broken away, with portions shown in diametrical section;

F ig. 2 is a section on the line 2-2 of Fig. 1, showing the normal operation of the lock; and

Fig. 3 is a similar view showing what happens when it is attempted to pick the lock.

It is well understood that in picking a lock of this character the cylinder is turned slightly by the introduction of an instrument "i so as to hold the tumblers 11 against the side of the slot in the casing 12 in which the tumblers pass outwardly in a radial direction. This is necessary in order to apply a little friction to keep them from slipping bac-k and enabling the person trying to pick the lock to manipulate them so as to unlock it.

This lock is constructed in all respects in accordance with an ordinary lock of this type, with the pins and tumblers 11, except that the passages or slots 13 in which the tumblers 11 work are cut out at both sides to form inclined recesses 14: large enough to receive these tumblers and having stop shoulders at a distance from the cylinder less than the length of the tumblers. The sides of these recesses can be made radial or nearly so.

Now in picking the lock it is necessary to turn the cylinder 10 by an instrument as indicated in Fig. 3, and then work in to push the tumblers 11 upwardly. In an ordinary lock they are forced to go straight up in opposition to their springs 16, but 1n this lock, on account of having to turn the cylinder, these tumblers will swing over, as shown in Fig. 3,

' and come up against the sharp shoulders 14.

every alternate one or even to a single one of them.

It will be noted that the two recesses 14 are located at the sides of the ordinary slots and project out circumferentially, so that the ordinary slots can be located as close together as usual, and that they are so placed that it is a very simple matter to drill them or cut them in any other way. Thus very little expense is added to the cost of the lock,

and it is rendered comparatively safe, so that it can be picked only when taken to a lockcuiv smith who will have plenty of time to work on it. The opening of the lock by unauthorized persons is ordinarily prevented by the simple device.

Although I have' illustrated and described only 'a single form of the invention I am aware of the fact that changes can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore, I do not wish to be limitedto the exact form shown except as set forth in the claims, but what I do claim is 1. As an article of manufacture, a lock comprising a casing with a cylinder rotatable therein and the usual pins and tumblers in the cylinder and casing for locking the cylinder in position, of stops in the casing whereby when the cylinder is turned slightly, and the tumblers projecting into the cylinder raised,y said tumblers will pass to one side and their outer ends be positively stopped in position against said stops.

2. As an article of manufacture, alock of the character described comprising a casing, a rotatable cylinder therein andthe usual pins and tumblers, the cylinder having a main radial slot for receiving a tumbler when it is projected from the cylinder, and a side recess located at an angle'with a shoulder at the extreme end in position to engage the end of the tumbler When swung into the side recess 5 and prevent the tumbler being entirely Withdrawn from the, @ylnden 3. ln e lock 0f the Characterv described, the combination of a casing or frame having a radial slot, a cylinder rotatable in the casing 10 or frame, a looking tumbler lnnvable in the cylinder and in said slot, and a spring in the slot to hold the tumbler normally in proper y position, the cylinder having a side-reeesson each side of the main slot for reeivin the n 15 tumbler when it is attempted t0 pick thelocl` by Slightly turning the, cylinder, Seid ,Side rcess 'ha-vine Smulders lodated at a distance from the cylinder less .than the length of the tumbler, e@ In testimony whereof I have hereunto affixed my Signature. Y

LOUIS C. GUTMAN. 

